HTTP-REST is an ESB
a recent thread on rest-discuss revolved around whether to use an existing ESB to help turn some legacy interfaces into REST-ful ones.
for me, HTTP-REST *is* an ESB. a well-designed and implemented HTTP application provides all the details for a fully-functional ESB. and, in the long run, one that requires much less 'diddling' over time. and - more to the point - one that is vendor-neutral.
really, i can't think of a better service bus for distributed applications than one based on HTTP. i know that reliable messaging and some other items are harder over HTTP. but not impossible. and HTTP is such a pervasive and universal protocol that it seems silly to use another. add the fact that RDF/SemWeb is growing stronger and i think it's smart for everyone to start thinking of HTTP-REST as the new ESB.