Hmm that's quite longer from my past experience, but not unheard of. What troubles me is that your pages haven't disappeared completely from Google's index, e.g. if you enter "site:korokithakis.net" there are 302 results returned.

Perhaps Google has reevaluated your ranking for these keywords, as there are a lot of PR6-7 sites but yours is a PR4 (at least according to the SEO Site Tools extension).

Your best bet is to follow infinity's advice and start blogging more frequently, while targeting specific keywords for your posts.

Ah, that's too bad then. All the tutorials used to be on the top of the results, so wouldn't they at least slip a few places down? I don't think they'd get removed completely if that were the case...

Not necessarily, for example your "Learn python in 10 minutes" post appears as a PR0 page, thus it won't outrank your competitors. Keep in mind that this could be just a temporal glitch and might get fixed automatically if/after your page is assigned a higher PR.

You mentioned that you've set up redirects from the old site to the new one, are you sure that your content doesn't appear twice, using different url's? (ks.net/node/1 and ks.net/tutorials/First) This will be penalized by Google.

Also your /tutorials url redirects back to the main domain, is this by accident?

Oh wow, that'd be why they don't appear, then. It used to be PR 5 or 6, now it's 0? All the old URLs (/node/<something>) are now redirected to the canonical ones, which is as it should be...

/tutorials/ points to / because I removed the page that was there and linked to them in the sidebar. I have no idea why Google would take the site from 6 PR to 0, wow...

There is absolutely no correlation between having a high Page Rank and outranking competitors. Go search for "hacker news" in google and you'll see that www.thehackernews.com (a PR 0 url) outranks twitter.com/hackernews (a PR 6).

The reason your site dipped out of the rankings is because when Google crawls a site and there have been significant changes to the structure (new theme, new internal linking structure, missing pages, etc), they yank you out of the index in order to reevaluate your proper position before moving forward. This can take a day, a week, a month, or half a year to recover; there is no way to predict how long it will take.

Try and replicate as much of your old site's structure as soon as possible, and just give it time.

I will do that, thank you. The old site structure was quite messy, with ugly URLs and links going back and forth to pages. I think this new scheme is much cleaner, now, as it's just a few links to pages. I'll try to add some categories or tags, though, and see how it goes.

Thanks again!