In Computer Science, does a presentation of findings at a conference constitute a "publication"?

There are two types of publications in Computer Science:

1. Publications in peer-reviewed conferences with published proceedings
2. Publications in journals

If you present your results at a conference or workshop but don't publish them in the conference proceedings — it's not a publication.

In general, publications in top tier conferences are much more important than journal publications for computer science researchers. Usually you can first publish your paper in conference proceedings and then submit it to a journal but not the other way around (though, of course, that depends on conference and journal policies).

Just to add to concise and to the point answer by Yury:

• there are also books, and if you publish a chapter in an edited book, it normally does not influence your publication record much (a paper in the proceedings or an article in a journal would value much more).
• however, if you publish a book all alone or with couple of co-authors (monograph, handbook or textbook) then it is valued even more than a journal article or a proceedings paper
• if you publish an edited book (a collection of chapters collected by a group of people - editors, and possibly peer reviewed) it is also valued, but normally less than a monograph