The new tool for backlinks analysis is available at http://ahrefs.com since march 2011. It provides lots of useful backlinks statistics for your and your competitors' (or everyone else's) sites.
Distinguishing feature of this tool is an independent database refreshed in realtime (circa 6 billion external and 25 billion internal links added each day). Ahrefs.com uses custom crawler to fill this database and is not affiliated with other search engines or similar services.
You're welcome to try new possibilities on any URLs you are interested in!
Ahrefs.com provides several free and paid service offers depending on the depth of information being analyzed.

Here is a new great feature by Ahrefs.com! Ahrefs Top ordering the most significant internet-projects by their referring IP's quantity! Who is the first million of Internet by objective criteria of referring popularity? Monitor them at http://ahrefs.com/ahrefs_top.php !

Here comes a new possibility of importing data from Site Explorer into the CSV and Excel formats. It allows saving data on your computer for further analysis.

For subscribed users there appeared a new type of report - Raw Export Report. It enables exporting up to 5 million links for any domains. Users with Starter Subscription may export 1 million links, those with Standard Subscription - 5 million links every month over a subscription period.

New free option is in the pipeline - trial usage of all paid services. You can build 3 standard reports for 500 links for any domain (not necessarily yours) for free, as well as to export 10000 links through rawexport. These limits are enough to analyse the efficiency of reports and export functioning. If you like the result you get and want more info, you may subscribe and get considerably higher limits.

We've been planning to launch API in the end of August, but already now we get many letters with API request and in connection with the fact that Yahoo Site Explorer API is going to be shut down, we've decided to launch version 0.1, which may be used right now.

Current API version enables:
1.to see links on the indicated domain, directory or URL
2.to see info about pages on a domain or in a directory

More advanced options will come, as promised, in August. To read more about API 0.1, follow this link - http://ahrefs.com/api/

With the recent launch of SERP database analysis Ahrefs has become "two in one" project. SERP's database uses about 45 mln keywords. It contains 9 databases of keywords for different countries. Only those keywords, which are searched for more than 30 times a month, are included into this database, thus only important info is given, without unnecessary garbage reports.

First 100 positions in a SERP are being analysed. This makes it possible to see popular keywords, by which site appears in SERPs and which don't bring traffic so far, thus they couldn't be observed by other means. This makes it possible to see popular keywords, by which site appears in SERPs and which don't bring traffic so far, thus they couldn't be observed by other means. And knowing these keywords it would be possible to get better position in SERPs with a wet finger. This option is really vital in doing SEO for a site.

The database is partially updated every day, full update cycle completes in 10 days. Thanks to that fact it is possible to observe dynamics of site ranking in search engines. New "Daily Stats" report shows everyday changes for a site:

1. number of new keywords by which site appeared in SERPs
2. by how many keywords site disappeared from SERPs (top 100)
3. by how many keywords site moved up in SERPs
4. by how many keywords site moved down in SERPs
5. number of positions lost by all keywords
6. number of positions gained by all keywords
7. ranking change (ranking or rating is the value of month search engines' traffic)
8. changes of this traffic price (rating*average bid in PPC).

Daily Stats makes it possible to observe all changes with the help of graphics. Directly from Daily Stats just with one click one can see new keywords, lost keywords, SERP positions up or down (!!!) Position Analysis shows by which keywords and at what place specified domain or URL is found. One can see data from 9 different countries.

Export to CSV is also enabled. Ads Analysis is another section, where one can see by which keywords specified site or URL has its ads in Google or Bing.