asp.net notification using SqlDependency

[al3x]

i'm using sqldependency in asp.net application to notify users with update (new comment added ,someone join his group etc ).this update change frequently and for each user new subscription add (as the query change based on login user)i want to now is it the best practice to use in this case and if yes ..what's the maximum number of subscriptions allowed before it affect performance thanks in advance