I have a multisite network, and one of the subsites uses a post-injection for the article page and sidebar widget for archive pages. This worked beautifully....until we attempted to use the plugin on another subsite. The post-injections from the first site somehow crossed over to the second, even though the ads/images do not exist on the second site. So strange.
Paid a lot of money to the developer for this to work on multisite networks, and all he can offer is that I'm stupid and set up my sidebar widgets incorrectly. What???? I'm questioning my post-injections, not the sidebar.
Don't waste your money if you have multisite...he obviously doesn't have a clue what he's doing there.