With the survey page type, you can create the kind of short answers you’d like to collect, and it’s easy to review and even export them. Be sure to set correct privacy settings when creating the survey, based on whether or not you want participants to be able to publicize their answers.
As of an hour ago, I've got 37,042 email and social media contacts in my personal NationBuilder database (maybe more like 35,000 total people - I've been a bit lazy with my deduping). And this isn't just a numbers game - my nation is a foundation for things I want to get done in the world, a personal version of the customer relationship systems (CRM) that companies like Salesforce and Microsoft provide for large businesses. It's tailor-built by me as essential infrastructure for organizing my supporters, contacts and prospects from around the world.
I've created a website with a signup page and mission statement, a custom volunteer page, and a set of database tags that allow quick targeting of messages to specific groups. I know how many of my people came from Empire Avenue (352), Google+ (249) and LinkedIn (2,074) and from signup lists for San Francisco Bay Area civic tech events (456). I tap into my nation when I want to do something like push a petition and rally support for an issue I care about (118 people signed my recent petition for an open data legal standard in California).
Using NationBuilder's lists feature, I can retarget emails to my strongest supporters - after I send an email, I grab the list of people who opened it and create a new list for a followup call to action.
I also create custom filters of my Twitter and Facebook connections to sort by Klout and by PC (NationBuilder's currency) and target by geography - like, in advanced search, selecting on the default section the "Following broadcaster" dropdown for my account, then under address, a city.
Once you've created a search, you can save it as a filter and then under People you can select that filter and "sort by" in the dropdowns to see those folks organized by Klout or by PC (the metric for a person's engagement level or network value within your nation). This is really useful for stuff like making sure you touch base with key connections while traveling - sometimes I use it just to identify and say "hi" with a tweet to influential connections in a city I'm in.