This is a start:
The Term Extraction service provides a list of significant words or phrases extracted from a larger content.
It can be implemented by making use of the Yahoo! API . One might then need to sort out the result set a bit and use them as \”tags\”. Since this blog has no cache and the API only lets me have a limited number  of requests a day, I will not dive into it yet 😉 For those using PHP, there is a so called yahoolib availabe.