Dax formula for datetimeline

hi  Vizbaby ,

not sure if i fully get you, try to 

1) add a calculated table like:

dates = 
ADDCOLUMNS(
    CALENDAR(MIN(data[Start Date]), MAX(data[End Date])),
    "Year", YEAR([Date])
)

Don't join the dates table with your data table. 

2) plot a table visual with dates[year] column and measures like:

ActiveMembersCount = 
VAR _year = MAX(dates[year])
VAR _list =
CALCULATETABLE(
    VALUES(data[Name]),    
    FILTER(
        data,
        AND(
            YEAR(data[Start Date]) <= _year,
            YEAR(data[End Date]) >= _year || YEAR(data[End Date]) = BLANK()
        )
    )
)
RETURN COUNTROWS(_list)

NewMembersCount = 
VAR _year = MAX(dates[year])
VAR _list =
CALCULATETABLE(
    VALUES(data[Name]),    
    FILTER(
        data,
        AND(
            YEAR(data[Start Date]) <= _year,
            YEAR(data[End Date]) >= _year || YEAR(data[End Date]) = BLANK()
        )
    )
)
VAR _listpre =
CALCULATETABLE(
    VALUES(data[Name]),    
    FILTER(
        data,
        AND(
            YEAR(data[Start Date]) <= _year-1,
            YEAR(data[End Date]) >= _year-1 || YEAR(data[End Date]) = BLANK()
        )
    )
)
VAR _newlist = EXCEPT(_list, _listpre)
RETURN COUNTROWS(_newlist)

it worked like: