Questions about using Google Translate and similar Apps seems to occur on the forum on a fairly regular basis. I recently came across a well written analysis on the subject and thought it may be of interest.
My experience has been that while these can often provide an approximate translation that "sort of" gets the idea across, they're completely wrong in some cases. This has been confirmed when I've asked native speakers of French, German and Italian. Translators seem to work best on short, simple sentences but not so well on longer sentences where context might be important.
For those who are interested, THIS ARTICLE provides a good analysis of the effectiveness and limitations of electronic translators. One caveat to mention, it's a long article.