Yahoo pipes: this service famous for a while ago, a little bit confused. but now this service no longer available.
RSSMIX: its OK but no login registration for users. All we have to enter up to 100 feeds and click to add their database.
A new RSS feed will generate. We have to copy that RSS feed.and burn with Feedburner, because every time you add a feed RSS mix feed URL will change.
So there is no customization after you generating the feed.
Feedburner maybe doesn’t accept the RSS feed from Yahoo pipes.
These services are just for education purpose, not works like professional.
I have combined 5+ jobs websites feed using RSS mix. And added to Feedburner. We can edit the feed burner original URL without changing the Feedburner URL.
With Feedburner feed, I tried post-Facebook and twitter automatically using twitter feed. But in my Facebook page I am database errors from WordPress website.
Also, twitter feed can check up to 5 posts for minutes interval.
Finally, I removed the feed from the twitter feed. Auto posting my new posts directly from WordPress dashboard individual from every blog. Now no problem it automatically sharing without any time gap. Posting on Facebook, Twitter, Google plus, Tumblr for linked in it not posting company page directly on the profile.
So I have to find new services or leave this to save my lifetime.
ChimpfeedR: this is better and optimized for mail chimp email service.
I have created master RSS feed using RSS mix and Chimpfeedr. All of are WordPress feeds.next step use this temporary feed to a permanent feed ID like Feedburner or MailChimp email service.
Other 5+ RSS mix Aggregator services available including Feed killer, Blat Casta, Feedinformaer, Turpie and rebel mouse.
we can combine feeds using RSS readers like Feedly and Digg feed readers. all we have to do is cache the Feedly RSS feed.
Use Mozilla firefox to check any visual changes because chrome will not work for that case. read more on Chrome vs Mozilla.