We are in the process of developing an API to allow our users to retrieve the data for WebStatsChecker.com and LinksRank.com.

We are planning the following functionality:

1. Keyword tracking

• First 100 positions in the search engines (at this stage only Google.com, but we might extend this to other search engines)
• Historic information for the keywords
• Exact and broad Google CPC

2. Domain rank tracking

• List of all keywords a domain is listed for and their positions
• Performance information & history e.g. Alexa, Compete, pages indexed in the search engines, backlinks shown by the search engine
• Number of Keywords in top 1, 3, 10 and 100 history

3. Backlink information

• Number of backlinks from different domains
• Anchor text for each backlink

Please feel free to suggest some more.  If we add your suggestion, you might just receive free access to the API.