Groups can be set to either "Public" or "Private" by a Group administrator.
Groups set to "Private" are not viewable on the web except by MyFitnessPal users logged into their accounts, who have joined that Group based on an invitation from a current Group member.
As a result, the contents of Private Groups cannot be indexed by search engines because that content is not accessible to their indexing programs.
Groups set to "Public" can be viewed (and joined) by any MyFitnessPal user. Public Group content may be found by performing general searches of the web using any popular search engine.
If you are uncertain whether a Group you belong to is public or private, please check with your Group's Creator or Leader.