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No, Steemit doesn't let follow tags, but you can use an RSS feed like so (based on this article):
http://createfeed.fivefilters.org/extract.php?url=https://steemit.com/created/TAGHERE&in_id_or_class=articles__h2+entry-title&url_contains=
Just replace TAGHERE with the tag you want.

Unfortunately, you can't use this to make items appear in your Steemit feed.

Oh, bummer. I may end up trying the rss feed though, so thanks for that link.