For years, a traditional publishing model has required that potential authors sign over the copyright of their article to the journal publishers as a "normal" part of the publication process. This seriously limits your rights as concerns your own publications, including whether you can post it (self-archive) on your own website or in your institution's research repository. Times have changed and you need to be aware of your rights in order to make informed choices that are best for you.
As an author, consider your rights when you're looking for suitable journals for your article. Important questions to ask:
Do you have a choice? Yes, you certainly do! You can negotiate with publishers over you retaining copyright. At the very least, this lets them know you along with other potential authors want to retain your rights. As an informed author, you can search for a different journal - perhaps an Open Access journal - that better meets your needs. There is also an increasing number of journals that are not totally Open and yet are allowing authors to retain some rights over their articles too. Here's how to find them:
SHERPA / RoMEO is a unique database that helps you know what rights specific journals will allow you as author to retain!
Just search your journal by name in SHERPA / RoMEO. You'll quickly see if you can retain copyright, and which version(s) of your work (pre-print, post-print, publisher's version) you can post ("self-archive") and where, plus any special conditions you'll need to follow.
You can use the information you find to guide your decision on which journals to choose for your publications.