Bed & Breakfast inns can be an economical alternative to pricey hotels, or a charming alternative to Spartan dorm rooms. This chart summarizes information on Cambridge and Somerville B&Bs from websites BedAndBreakfast.com (BB), TripAdvisor.com (TA), and HarvardStudentAgencies.com (HSA). Like all data off the Internet, it likely contains many inconsistencies, errors, and outright lies; it should be used only as a starting point. If some feature is important to you, confirm it with the inn.
Some inns that do allow children have a minimum age, others will take babies and toddlers. The few inns that allow smoking at all generally allow it only outside; some non-smoking inns have hefty fines for violators. Parking may be private, or on-street with a loaned permit. A blank under a heading such as "parking" or "website" doesn't mean there isn't any, just that they don't claim it.
BB is an industry group, so it's not surprising that their ratings span the limited range from 4 to 5. They have the best and most consistent listing of amenities. TA's ratings are more diverse and believable (nobody gets a 5, for one thing) and their reviews are worth checking out. HSA doesn't have many reviews, but the ones it does offer are more in-depth than the other sources.
A question mark indicates inconsistent data among or within sources, and rates in particular are likely to vary greatly. When communicating with individual inns, it might be prudent to avoid referring to "graduation" or "reunion"; many of these inns charge significantly more for Harvard Graduation week (one week before our reunion).
The B&B Spreadsheet