My favorite article-clipping service just got even better. A few months ago, Instapaper was acquired by Pinterest, in the usual tech-company deal we see these days when one company thinks that the technology another company developed would make its own products and services even better. Google and Amazon have done this countless times.

But rather than the usual case, in which the acquiring company shuts down the company it just bought (as was the case with Google and Etherpad, or Safari Books Online and Ibis Reader), Instapaper has announced exactly the opposite is happening: not only will Instapaper’s services be continuing, but the add-on services that formerly required paying for a premium account will now be freely available to everyone. Those who’ve already paid for Instapaper premium accounts will have pro-rated refunds coming within the next week or so.

These premium services include zero ads on site or mobile app, full-text search for all articles, unlimited use of the text-highlight notetaking feature and speed reading, text-to-speech playlists, a bookmarklet for emailing articles instantly to one’s Kindle without having to run them through the Instapaper site or app first, and the ability to have up to 50 articles included in the nightly “Kindle Digest” rather than the 10-article free-account limit. Instapaper also offers the ability to download MOBI or EPUB versions of your current document collection, as well as an experimental “make printable” option and an RSS feed.

(Unfortunately, I can’t seem to get the MOBI to download directly to my Kindle, due to some issue with their MOBI generation system not being compatible with the Kindle’s experimental web browser. But I’ve never had any problem with the automatically-generated nightly digest.)

In the blog post announcing the change, and discussion in the comments, the Instapaper team explained that they’re able to make this change because they have low operational overhead, and Pinterest sees value in keeping the service running. Instapaper rep Brian Donohue explained, “The value that Pinterest gets from Instapaper are improvements to our text parser and aggregate information about links on the web. We have no plans to serve ads.”

Some users expressed concern that Pinterest might be mining personal data as part of that “aggregate information,” but Donohue explained that Instapaper’s privacy policy was not changing and would still be strictly honored. Instapaper would only be providing general information on things like which articles were bookmarked the most times, with any personal or identifying information removed.

So, apparently Pinterest believes it can make Pinterest even better by keeping Instapaper running as a metadata generator. Thus, it’s willing to subsidize those “low overhead” costs, even in terms of providing Premium service levels to everybody. The more people use the service, after all, the more useful metadata it will generate.

It doesn’t really surprise me. That’s the way tech companies work these days. Perhaps the most fitting analogy would be Amazon acquiring Goodreads but keeping Goodreads running just as it is, because the metadata Goodreads produces helps improve Amazon’s services.

In any event, I never thought I would use enough of those premium services to make paying for Instapaper a consideration. But now that they’re available for free, I’ll certainly take advantage of some of them. They certainly could be useful to people who make a lot of use of their Kindles or other e-ink readers, and would like to read news articles there as well.