We can transform any individual site tags as rss by simply going to [sites].tumblr.com/tagged/[tag]/rss
and we can also see global tags result by going to tumblr.com/tagged/[tag]
However, tumblr.com/tagged/[tag]/rss
isn't a valid page. Is there any API or 3rd party service to transform the global tag into RSS?
Best Answer
This is not currently possible from Tumblr itself, but you might be able to use a 3rd party service like that offered by FiveFilters.org to create an RSS feed from the Tumblr global tag page: http://createfeed.fivefilters.org/
Enter web page URL:
http://www.tumblr.com/tagged/cat/
Look for links inside HTML elements whose id or class attribute contains:
post_content
Only keep links if link URL contains:
/post/