Abbreviations are terrible for searchability. For example, a DDG search just now told me that ECC could mean Erie Community College, Elgin Community College, El Camino College, or Essex Community College. Of course it's easy to find out what "error-correcting code" means once I know that that's for what "ECC" stands, but that latter fact might not be so easy to discover. (In this particular case, it's the 5th DDG result, but I've definitely run into abbreviations with no plausible expansion, or, which is perhaps worse, multiple plausible expansions.)
More importantly however, if a phrase is uncommon, then one person asking and one person answering can save hundreds of people from searching and thousands of people from not searching and not knowing.
HN is not like other sites. It is for informed discussion that adds depth to the topic. If I want a linkfarm of relevant topics, I can easily go to Google or Wikipedia. If I want to see karma whoring for copy+paste links, I can go to Reddit. HN is not going to stay more informative than other sites if we are satisfied with discussing basic topics.
edit: What are you people downvoting for? I'm not insulting anyone. I just frankly pointed out how I would interpret the attitude of the person asking as above.