100,000 people is pathetic.
Note that this is not subscribers - this is "the total amount of people who have paid in one way or another". 50,000 of those are subscribers, which in PR-speak probably means "people who have subscribed" i.e. not the current amount of subscribers.
With an in-built audience of over a million in circulation, plus a reach that goes far beyond that, an ad campaign AND the novelty value of "new", getting less than 0.5% of your audience to pay for online (it's not even 0.5% - some [most?] of these people have an online subscription because of their print subscription) means either a piss-poor job is being done converting users, or this business model is a dud.