Pinging yahoo.com [216.109.112.135] with 32 bytes of data:

Reply from 216.109.112.135: bytes=32 time=342ms TTL=48
Reply from 216.109.112.135: bytes=32 time=375ms TTL=48
Reply from 216.109.112.135: bytes=32 time=362ms TTL=48
Reply from 216.109.112.135: bytes=32 time=378ms TTL=48

Ping statistics for 216.109.112.135:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 342ms, Maximum = 378ms, Average = 364ms

Thank you for your message concerning the Comcast High-Speed Internet service.

We are currently experiencing an outage in your area concerning intermittent connection and slow speeds.

We apologize for this inconvenience and are working toward a resolution as quickly as we can.

We hope to have the service restored shortly but do not have an estimate as to when this will occur.

We thank you for your patience as we investigate the source of the outage and make the necessary repairs to the network.

Your service during the last few months from about 7 pm until midnight
has been terrible.  This is hopefully another email from a frustrated
customer pointing to the egregious latency problems (such as avg. ping
ms to yahoo.com being 300-500 with samples of 100) your network has
been having.  Yet your technical support does not desire to rectify
the problem - calls to support only suggest that the faulty node is at
the individual user's router or modem.  But that is not the case, and
given the volume of emails like this you've undoubtedly received, I
recommend taking action if you want to maintain your customer base.
You will not survive to compete with other ISPs (hopefully some will
move up here, or is your plan to maintain monopolistic domination over
the area and ignore the cries of terrible service?).
I recommend passing this email to your manager, as I do not want a
canned email response explaining the uncertainty of the source of this
problem.  The source is clear.  The only question is whether steps
will be taken, or whether the loss of one direct (and many more
indirect, because this service has been outrageous to the point that
your reputation will suffer far greater losses from recommendations
against fellow bay area residents) customer will make a difference.
I certainly hope it will.