Content aggregators and distributors are wonderful enterprises. Life would surely be different if you consumed all your media directly from the original sources. In some cases it would be a good different as those producers would get more direct feedback. In other cases it would be a bad different as exposure would be more random and time would be wasted by many people searching for similar things.
Baseball stories are like that, especially during the awful rumor season. People, many people, want the latest dish on offseason moves, 99% of which will not come to fruition. Subscribing to every baseball beat writer and internet gossip columnist would generate a lot of fluff to wade through looking for whatever you felt were the juicy bits. So I totally understand the appeal of sites like MLBTradeRumors (MLBTR). I really do. It's a very valuable collection service.
They are not however, most of the time anyway, producers. The site doesn't make the content, it collects it. There's nothing wrong with the latter, but I am asking that if you too wish to share some piece of news or "news", that you make sure to include a link back to the actual producer of the story. That's where the majority of the internet credit should go. MLBTR themselves do a fantastic job of that as every post and update they push out contains links back to where they are getting their information from, if it comes from an outside sources. I ask you, everyone, to do the same.
That doesn't mean totally avoid linking to MLBTR. They're not [redacted] or someplace similar who deserves nothing but web silence. The rule of thumb I advocate is to make sure to always include the original source and, if there's any interesting commentary, links to that additionally. It may take an extra second or two, but not much more than that, and it's the decent thing to do.