NAA has most of the features you would expect to find in an antivirus solution: it supports scheduled, on-demand and real-time scanning and also scans email, instant messenger and newsgroups communications for threats. Because NAA works at the protocol level, it will work with any email, IM or NNTP client (which is good news for people who use something other than one of the mainstream products).
There are, however, a couple of rather odd omissions. Like most antivirus solutions, NAA uses heuristic (or behavior-based) detection in addition to signature-based detection. But unlike most solutions, NAA does not enable you to adjust the sensitivity of its heuristic engine. Consequently, you cannot increase sensitivity in order to enhance detection and nor can you decrease it in order to reduce false-positives. NAA also does not offer any form of centralized management to enable you to manage and monitor the installations across your home network.