Problem: someone deletes a post from his/her blog. I want to recover the post.

Situation #1: I subscribed to that blog and the feed is full -> Problem solved (if the feed reader is fast).

Situation #2: I subscribed to that blog and the feed is partial -> I can only see a snippet (if the feed reader is fast).

Situation #3: I didn't subscribe to the feed

-> I can do a search in Google BlogSearch/Technorati and get some snippets depending on my query.
-> Coral cache
-> Quick spam blogs
-> Maybe subscribe to the blog in Google Reader (does this work?).

For #2, #3, the solutions are only partial. Is there a blog search engine that shows the cache or other way to recover the deleted post?

This is something Philipp and I have discussed before. None of the big search companies seem to let you view the feeds they've cached, even though they must have a full cache of the feed item.

If the post is in Google Blog Search, you can try entering the exact text from the first sentence to get a snippet. Then, take the last few words of the snippet shown and search for that. And so on. By doing this, you may be able to obtain some more text from the feed item, although it obviously won't contain any formatting or images, etc. And if that doesn't work, you can try guessing words from the next section of the post to get more text.

Are you going to share which deleted post you're trying to recover? ;-)

Mabey you could make a search engine that does this? ;)

On that note, I just replaced the RSS parser used for the Google's Blogs aggregator here (MagpieRSS didn't parse the Google feeds correctly anymore, and the project is deserted, too, so I switched to simple XML parsing). This means that while I'm only showing a snippet from the post, I'm storing the full post in a local database for reference. That of course doesn't answer your question Ionut but I thought it might be of interest if ever the post in question is by Google...