It could be for splitting off the first word from a web server access log, where lines could look like eg.

95.108.157.251 - - [23/May/2011:19:02:56 +0000] "GET / HTTP/1.1" 200 9
+6 "-" "Mozilla/5.0 (compatible; YandexBot/3.0; +http://yandex.com/bot
+s)"
[download]

Though in that case, splitting on a dot might not be a good idea, especially because the first field could also be an ipv6 address, such as 2001:738:2001:2010:0:ff:fe00:3.