Not much.
At least in my field, most published abstracts come from submitting a presentation to a conference and having it accepted. The abstract is then generally published in a supplemental issue of the journal for whatever society is hosting the conference. Not every society does thisl, but a fair portion do.
Even the more competitive conferences usually have very high acceptance rates for conference posters compared to journal submission acceptance rates, so its really not hard to do. It may vary somewhat by field but you would have to produce something truly spectacularly awful for it to not be accepted at SOME conference. This is why published abstracts are generally not viewed as "real" publications and don't count for much.
