Can I collect meta information on papers and put this online?
With the hopefully obvious caveat that I'm not a lawyer and this is not legal advice: at least in the US, this is probably fine. Copyright law (17 USC § 102) applies to "original works of authorship," not to ideas, and I think everyone would agree the metadata of an article's publication (including journal name, author, and date) fall in the latter category, not the former. Otherwise the whole system of academic citation would be untenable!

The title and abstract, on the other hand, are content created by the articles' authors and are protected by copyright law, but I think it's quite likely that fair use (17 USC § 107) protects you from being held liable for using them in the manner you describe. With reference to the four conditions to be considered when determining fair use:


  (1) the purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes;


You say it's a free, noncommercial endeavor, so that works in your favor


  (2) the nature of the copyrighted work;


It's an academic article; the whole purpose of its existence is to be widely disseminated


  (3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole


The title and abstract are a small part of the work


  (4) the effect of the use upon the potential market for or value of the copyrighted work


Using the title and abstract in a database like this will more likely increase the market for the original paper than decrease it (which is in fact the entire point of having an abstract)



In fact, you would hardly be the first person to do something like this. In high energy physics, INSPIRE already aggregates abstracts and metadata from nearly all published papers.