Google mentioned in many occasions that it doesn't want to trap users' data and some of its services have started to provide import/export options. Here are some of the ways to export your data from Google's services:
* iGoogle lets you download the list of gadgets, feeds, themes and their corresponding options if you go to the settings page and scroll down to the "Export / Import" section. The resulting XML file can be imported to another Google account and those who are familiar with XSLT could covert iGoogle's data file to OPML, so you can subscribe to the feeds in Google Reader or any other feed reader.
* Google Calendar has options to export your calendars one by one as iCal files, but it's much easier to export all the calendar you created by going to: http://www.google.com/calendar/exporticalzip.
* Google Docs lets you export your documents as an archive of HTML files and images. To export your files, restrict the Docs list to documents, select all the files and choose "Save as HTML (zipped)" from "More actions". Zoho can already import your documents and there's a Greasemonkey script that helps you download all the files from Google Docs, not just the documents.
* Blogger added in the experimental version available at draft.blogger.com an option to export the posts and comments from your blogs as an Atom feed. Hopefully, developers will write scripts that convert Blogger's feeds to the formats accepted by other blogging services.
* Google Bookmarks can be exported as a HTML file, but for some reason browsers can no longer import the bookmarks. The web history or search history can be exported as a RSS feed: http://www.google.com/history/lookup?q=&output=rss&num=1000 (replace 1000 with the number of items you want to export).
* Gmail lets you export your contacts as CSV or vCard, but Google automatically adds all the people you send a reply in the list of contacts.
It would be nice to export all your data from a single page, so you can delete a Google account or switch to a competing service without losing your data.