Splitting the sentence up to add a link in the middle will make it impossible to translate correctly into other languages, so it's best to use a placeholder to insert the link, e.g.

    <%= (_("You can find The Foreman on the %{freenode} network, etc etc") % {:freenode => link_to(.....)}).html_safe %>

Note I've put another set of brackets around and used .html_safe to ensure it renders actual HTML.