This list of tag pairs that differ by hyphen. The number inside brackets was number of question tagged with that tags.

* [tag:port-forwarding] (688)   [tag:portforwarding] (57)
* [tag:web-services] (82)   [tag:webservices] (30)
* [tag:mod-security] (142)  [tag:modsecurity] (25)
* [tag:keepalive] (81)  [tag:keep-alive] (21)
* [tag:opensource] (125)    [tag:open-source] (16)
* [tag:virtualpc] (79)  [tag:virtual-pc] (16)
* [tag:reporting-services] (126)    [tag:reportingservices] (14)
* [tag:web-farm] (48)   [tag:webfarm] (14)
* [tag:d-link] (21) [tag:dlink] (13)
* [tag:print-server] (126)  [tag:printserver] (12)
* [tag:read-only] (66)  [tag:readonly] (11)
* [tag:openmanage] (39) [tag:open-manage] (7)
* [tag:sqlserveragent] (34) [tag:sql-server-agent] (7)
* [tag:hostheaders] (24)    [tag:host-headers] (7)
* [tag:msword] (12) [tag:ms-word] (7)
* [tag:live-cd] (31)    [tag:livecd] (6)
* [tag:instantmessaging] (15)   [tag:instant-messaging] (5)
* [tag:contentfilter] (41)  [tag:content-filter] (4)
* [tag:visual-studio] (66)  [tag:visualstudio] (3)
* [tag:log-shipping] (26)   [tag:logshipping] (3)
* [tag:datetime] (17)   [tag:date-time] (3)
* [tag:.net2.0] (4) [tag:.net-2.0] (2)
* [tag:thumbdrive] (4)  [tag:thumb-drive] (2)
* [tag:virtual-drive] (3)   [tag:virtualdrive] (2)