Limit the number of characters for posted articles in the stream

Currently, when a user post an article, the whole article is displayed in the stream, we have no ability to limit the number of characters of the posted article content in the stream.
I still do not see why this feature hasn't been implemented, since it has been requested many times.
We also have no ability to strip HTML tags, so they show up in the stream with tags, etc...
It makes the stream looks ugly and unattractive ...