<PAGE>
VIALOG CORPORATION
CALCULATION OF SHARES USED IN DETERMINING NET LOSS PER SHARE
(Unaudited)
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<CAPTION>
Three Months Ended Nine Months Ended
September 30, September 30,
-------------------- --------------------
1999 2000 1999 2000
--------- --------- --------- ---------
<S> <C> <C> <C> <C>
Common stock, beginning of
period........................... 8,661,722 9,471,102 3,693,672 9,133,569
Weighted average common shares
issued during period, net........ 77,503 25,199 3,933,948 207,631
Common stock options and warrants
using the treasury stock method.. -- -- -- --
--------- --------- --------- ---------
8,739,225 9,496,301 7,627,620 9,341,200
========= ========= ========= =========
Net loss (in thousands)........... $ (2,478) $ (3,731) $ (9,403) $ (6,009)
========= ========= ========= =========
Basic and diluted net loss per
share............................ $ (0.28) $ (0.39) $ (1.23) $ (0.64)
========= ========= ========= =========
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