My view: Acronyms are somewhat more defensible for domain investors since initials can be representative of many unrelated identities ... typically none of which can claim comprehensive rights, but perhaps limited rights specific to their particular business classification. I have no idea what IDRA is, but it could be short for different organizations, companies, products, or services that have no connection to one another. As long as your use is distinctly unrelated to what other IDRA's are doing, then risk is minimal. Avoid "bad faith" by avoiding any connection or reference to any other IDRA products/services.
On the other end of the trademark continuum are highly specific marks like Pepsi Cola, Verizon Wireless, Ford Motor and typically there is no getting around this type of profound trademark protection. There is no way to utilize a mark like this without bad faith intent and creating confusing similarity. In other words, there is and can be only one "Pepsi Cola", and everyone in the world knows that without a doubt. So venturing in that arena is instant admission of guilt and infringement. Maybe some fair use leeway for Pepsi Cola Sucks, but why bother.
The other, MAEMO, and even longer acronyms might pose more risk. The longer the acronym, the more specific and singular (protectable) it's identity becomes.
