Alexa: Too often, dubious numbers

1Strengths: Alexa is good for comparing different sites traffic and for monitoring general traffic trends. It can be quite useful for comparing one site to a competitor site (up to five sites at a time). The index is massive and contains some data about all of the 25 sites we tested.

Weaknesses: Not so great for the smaller sites. As you can see below, you won’t get any of the traffic charts for sites ranked outside of the top 100,000, which means if Alexa thinks you are getting fewer than 10,000 visits per month you’re unlikely to glean any great information. Accuracy is a serious concern. This does call into question the usefulness of the tool in general. The numbers reported are not helpful for predicting traffic on their own.

Accuracy: We want to keep this all anonymous but let’s just say one site that we know gets 10-20,000 visits per month had an Alexa rank that was more than five times better than a site that we know gets 75,000+ visitors per month. And this was not just a one-off event. So I have to seriously question the reliability of this tool. It didn’t seem to be too bad at predicting the trends for a single site but the charts are extremely difficult to make any real use of. Interestingly it seems to be skewed in favor of sites within the search marketing space. Sites in the search marketing space that we looked at regularly outranked sites receiving more than 10 times as much traffic on a monthly basis.

How to best use Alexa: The tool is interesting for comparing similar sites or sites within an industry, but be very cautious about using this to make any meaningful suggestions or estimates on traffic data. The most accurate data seemed to be the data from the visitors by country — the percentages we looked at were not too far off.

Cost: Free. Options for site audits for $199.

Compete: Good UI, questionable data

2Strengths: Compete has a useful interface, speaks the right language (unique visitors, visits, etc.), offers the ability to compare multiple sites, and its data is easy to understand and well presented.

Weaknesses: Accuracy, somewhat limited number of sites – many sites that it classifies as “low sample sites,” and the cost of the Pro option.

Accuracy: Again, accuracy is a serious concern here. The data was off in some cases by as much as 2,000% for monthly visits. The accuracy seemed to be a bit better for the peaks in traffic and some of the general trends we looked at but was certainly not reliable enough for us to suggest reporting competitor traffic based upon this information.

How to best use Compete: It should come as no surprise that Compete is best used for comparing competitors. The scale of the data is way off but some of the trends seemed to be fairly reliable. I wouldn’t advise reporting any numbers from this data as they do not seem close/reliable at all – often off by a factor of 200% or more — however the trends are reliable. The information could be meaningfully used to look into seasonal trends between competitors.

Cost: Free. The Pro membership is $499 per month.

Google Ad Planner: Some unique twists

3Strengths: Google Ad Planner has a few things going for it: Its “sites also visited” data is good, the keywords searched for can be quite valuable, and the “audience interests” data is interesting.

Weaknesses:: Accuracy, lack of data for small sites.

Accuracy: The accuracy was really mixed. For many of the sites AdPlanner provided much better data than some of the others. However, they were still off by miles for some sites – off by as much as 1000%. Given the occasional “big miss,” I would not be comfortable using this data to make traffic predictions for a client.

How to best use Google Ad Planner: The data about other sites visited as well as keywords searched for (with affinity) could be extremely valuable as well as some of the other metrics reported on and audience interests. However, the traffic data is not particularly meaningful and can’t be relied upon.

Cost: Free.

Google Insights: Numbers normalized for search

4Strengths: Google Insights offers generalized trends around key phrases and key phrase groups and regional information. Trusted source.

Weaknesses: It was difficult to read the data. There were no hard numbers about traffic. It was hard to compare entire sites to one another.

Accuracy: You can bet that the accuracy of this data is going to be pretty good given that the data provider has access to more data than anyone else on the Internet. However, the fact that the numbers are normalized and more designed for key phrases and search terms and trends than for traffic data means that the search volume will correspond perfectly with the traffic to a site.

How to best use Google Insights: The tool could be quite helpful for finding the most valuable pockets of key phrases and key phrase groups. This could be particularly valuable when looking at a competitor site and trying to figure out which of their key phrases are driving the most traffic. It could help you see which of the key phrases within a key phrase group might be the most valuable.

Cost: Free.

Google Trends: For broad information gathering

5Strengths: Google Trends for Websites is good for illustrating magnitudes of difference between sites. It allows comparison of multiple websites, and it includes regional information.

Weaknesses: It’s not good for comparing sites fairly similar in size. It does not provide information for smaller sites when logged in, it’s accuracy is uneven and it provides no numbers.

Accuracy: The data seem to be more accurate when only trying to compare traffic from search; it does not seem to do as well in assessing overall traffic. When comparing websites with drastically different traffic numbers, the rough visual estimation appears to correspond quite well with the observed analytics data as well. When visiting the site and logged in, Trends it does provide numbers and ranges, though the data looks to be off on a few of the sites I have checked. It is not as far off as the data for the same sites using AdPlanner, but still considerably far off — e.g., reporting 140,000 visits for a site that receives about 320,000 unique visits daily.

How to best use Google Trends for Websites: Trends is great for broad information gathering. It gives some insight into similar searches when comparing sites, and in general it is unlikely that you will find better comparative data out there without direct access to your competitor’s analytics account. However, Trends does not provide numbers and thus can only be used to venture a guess at what sorts of numbers competitors are pulling in.

Cost: Free.

Quantcast: Nifty Media Planner Tool

6Strengths: Quantcast provides traffic numbers that are easy to follow, displays information nicely, offers some demographic information and has an interesting Media Planner Tool.

Weaknesses: Unreliable and often inaccurate, lacks data for small and medium trafficked sites. Inability to compare sites.

Accuracy: The biggest shortcoming of the Quantcast data is accuracy. As with some of the other services, the traffic data is estimated and is nowhere near accurate on the sites for which Quantcast had any data. Data was off by as much as 10 times the actual analytics data for some of the sites.

How to best use Quantcast: Although the data is not particularly reliable for the traffic data, some of the other tools the site has to offer seem quite interesting and worth further investigation. The demographics information provides a reference as to how the data compare against Internet averages.

Cost: Free.

SEMrush: Most accurate of the bunch

7Strengths: SEMrush‘s data includes sites of all sizes, a list of key phrases and rankings for those terms — and provided the most accurate data of all the tools we examined.

Weaknesses: The data were still imperfect. Customers must pay to get full data lists. And the data is only for Google traffic.

Accuracy: The data were not perfectly accurate, though generally speaking SEMrush did not miss the mark for any of the sites we tested the way a number of the other tools did. In the end, the data were surprisingly accurate. As with some of the Google data, the information reported is just the Google search engine traffic, but this is our main area of focus and was quite accurate when drilling down into that specific area of traffic within analytics.

How to best use SEMrush: Although imperfect, this tool came the closest to providing accurate data that I would, at least with a word of warning, be willing to share with a client about potential expectations or about where their competitors’ traffic may be. Most importantly, the add-on options and ability to see the keyword lists and how the competitor ranks for these terms is extraordinarily appealing.

Cost: Free to $499 per month. We used the free version.