

Ask HN: How to implement 'free trial' that is acceptable to Google AdWords? - MarkMc

Our company offers Windows and Mac desktop software that includes a free 30-day trial period.<p>In order to prevent the user from continuing the trial after the trial period expires, the software writes the installation date to a &#x27;hidden&#x27; place on the computer.  Crucially, this date is not deleted when the user uninstalls the software.  This prevents the user from repeatedly trialing the software without paying for it.<p>Google&#x27;s new AdWords policy [1] no longer allows this type of behaviour.  Specifically, &quot;Once an application is disabled or deleted, it may not leave any remnants&quot;.  Google support have confirmed that our software behaviour breaches this clause.<p>So my question is:  How should I modify the software to offer a free trial without breaking the AdWords rules?<p>So far I see two options: (1) Simply hope that the user does not discover that they can extend their trial forever by continually re-installing the software; or (2) Have the installation program send some unique hardware ID to an  online server to authorise the trial.  Which of these options would be better?  Is there a third option I&#x27;m missing?<p>[1] https:&#x2F;&#x2F;support.google.com&#x2F;adwordspolicy&#x2F;answer&#x2F;50423?hl=en-GB&amp;utm_source=policy&amp;utm_medium=email&amp;utm_campaign=gen
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Baliw
Option 2 is your best bet. There are several hardware ID's you can use.
Network MAC address is probably the least likely to change.

If you can't leave anything at all on the system then you have to use
something that's already on the system that doesn't change as a key.

~~~
caw
One caveat is that MAC addresses are not guaranteed to be globally unique. In
practice they may be, but with sufficient amounts of similar hardware you can
get duplicates.

Use the MAC if you're looking to make it silent. Use the free registration if
you also want to harvest emails for your marketing people.

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Ellipsis753
If you require them to sign up to get the free trial then you can allow each
account to only have 1 free trial. Then either have the free trial use the
account to activate or simple only let each user download once and have the
installer delete itself after installation. They will need another email
address and account to get another free trial so I don't think many people
would bother.

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benologist
Server-side user registration - you could put this together super easily with
[http://parse.com](http://parse.com).

